


Replace this pain (with something numb)

by Askellie



Category: Undertale (Video Game)
Genre: Fake Aftercare, Isolation, M/M, Mind Manipulation, Psychological Trauma, Punishment, Sensory Deprivation, Torture, Touch-Starved
Language: English
Status: Completed
Published: 2020-07-14
Updated: 2020-07-14
Packaged: 2021-03-05 04:21:45
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,119
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25258393
Author URL: https://archiveofourown.org/users/Askellie/pseuds/Askellie
Summary: Cross made a deal with Nightmare. That was his first mistake.Cross thought he could break his deal with Nightmare. That was his second mistake.
Relationships: Crossmare, Nightmare (Dreamtale) / Cross (Underverse / Xtale), Nightmare / Cross, Sans/Sans (Undertale)
Comments: 9
Kudos: 178





	Replace this pain (with something numb)

**Author's Note:**

> A what-if scenario set after the events in Underverse 0.3 Part 1 where instead of simply threatening Cross, Nightmare decides it's time to intervene before his new minion starts thinking he actually gets to act on his own.
> 
> (Kinda considering making this a series where Cross gets properly introduced to the rest of Nightmare's crew, and exploring how they interact with each other. Comments and encouragements would be welcome. :3)

All Cross can see is unending white. There’s no shapes or shadows, nothing breaking the endless pale horizon in front of him. It’s perfectly, agonisingly empty, and his horror conjures the sour-acid taste of panic to the back of his throat.

“Do you like it?”

Cross whips his head around, searching for the source of Nightmare’s voice. His dark, oozing silhouette would be a relief against all the searing white, but there’s no sign of him. Cross can hear him, can  _ feel _ him and the sickening weight of his aura crawling over his bones. He’s close enough that Cross can taste it, but no matter how he strains his eyelights he can’t see through the veil blinding his vision.

Cross takes a sharp breath. His voice comes out admirably steady when he says, “I already apologised. You don’t need to do this.”

“Don’t I?” Nightmare’s amusement rolls over him like a warm breath. His voice seems to be coming from everywhere and nowhere at once in a disorienting contradiction. “I’m afraid I disagree. You seem to have misunderstood the basis of our agreement. We’re not partners. My commands aren’t mere suggestions for you to ignore as it suits you.”

“Fine. I get it,” Cross agrees hastily. He’s trying to keep his bones from rattling, but he knows Nightmare can hear it. “You’re the boss. I’ll follow orders next time, just let me out of here.”

“Hmm, no, I don’t think I will,” Nightmare says. “I can feel your desperation, Cross, but no actual regret, so I think there’s still a lesson to be learned here...of the consequences for displeasing me.”

Something soft and oily brushes invisibly against Cross’s cheek. He flinches, brought up short by the bonds he can no longer see. Nightmare chuckles appreciatively at his discomfort.

“I’m sure after this we’ll understand each other much better. I’ll see you later, Cross.”

“Wait!” Cross blurts, casting aside any lingering thoughts of dignity. He lunges futility after the fading echoes of Nightmare’s voice. “I’m sorry, please, I know I fucked up, it won’t happen again, don’t leave me here-!”

The pressure of Nightmare’s aura fades away like pus draining from a wound, but the utter isolation left in its wake is somehow worse than the constant, subliminal feeling of unease. Cross’s breathing sounds too loud and ragged in the silence. There’s a faint rushing in his ears from the storm of pressure brewing in his skull. He tucks his face down into the ruff of his hood as a paltry shield against the emptiness, but the soft fur fails to provide any sense of comfort.

“Chara?” he tries hopelessly, but there’s not so much as a flicker of awareness from the empty soul fragment grafted onto his own. It was Nightmare’s first gift to him, a stronger seal to keep the human’s consciousness permanently locked away. Finally Cross doesn’t have to worry about lowering his guard inside his own head. He can sleep without fear, and when he’s awake there’s no more of Chara’s endless, cruel taunting whispering madness into his thoughts. 

But now the silence is all-encompassing; terrifying. He hadn’t thought there was anything worse than being trapped in the void with Chara in the wake of his own world’s destruction, but being completely alone is far more terrible. Even with his sockets shut he can feel the oppressive enormity of the space around him. He feels so small and insignificant, like he never mattered and never will again.

_ It’s not real _ , he tries to convince himself. The void is just an illusion; some kind of waking nightmare as per the other skeleton’s namesake. Before this, Cross was in a plain cell in the basement of Nightmare’s castle as a punishment for his transgressions. He can still feel the binding manacles keeping his wrists locked behind him and his legs folded in a repentant kneel. He flexes against the cuffs, trying to ground himself in the pain, but even though his rational mind suspects the emptiness around him is just a trick there’s no shaking the paranoid conviction that he’s living out his worst fears just as Nightmare promised he would.

There’s nothing to do but wait, and hope Nightmare grows bored of this punishment before Cross loses his mind to the crushing emptiness for a second time.

* * *

There’s no time in the void. There’s no way to know if it’s been hours or days since Nightmare left him. Cross counts his own breaths until delirious exhaustion makes him lose track of where he’s up to. He starts again. Forgets again. Screams in frustration until his voice is nothing but a weak, soundless rasp in his throat. Begs soundlessly in the hopes that Nightmare is still listening, that he’ll deign to put an end to Cross’s suffering. 

Nothing changes. It doesn’t end.

His tears of frustration fall down his face and just vanish into the nothingness. There’s no puddles of color left behind, and even if there were, he doesn’t think Ink would come to save him this time. 

The anguish gives way to a desolate apathy, and for a short while he thinks that’s a blessing. Better not to feel anything than be trapped in unending despair. It’s a bleak but peaceful reprieve.

Until the voices start.

It feels almost like another dream, but a happier one. His sockets flutter in exhaustion, and faintly he imagines his brother scolding him for staying up too late, for raiding the fridge after midnight again,  _ that’s not behavior fitting of a royal guard, Sans _ .

“Heh,” Cross whispers weakly. “Sorry, Paps.”

It’s followed by another conversation, this time Undyne playfully mocking him for his sloppy swordsmanship. Then Queen Toriel, asking if he wants to join her for a slice of the pie she just pulled out of the oven. Then Papyrus again, this time asking if he wants to train even though they’re supposed to have the afternoon off, because with Frisk’s life at stake it never hurts to be more prepared.

Normal, banal, everyday interactions that he misses so keenly it feels like his soul is breaking all over again. His shoulders quiver as he swallows down silent sobs. It’s already painful enough just remembering what he’s lost, but experience has taught it won’t stop there. His guilt isn’t satisfied by just tormenting him with pleasant memories. Not when it has so much more material to work with.

_ Give up, brother. _

No, no, no, he doesn’t want to remember this. He doesn’t want to live through it again.

_ Your hate killed our friends. _

The blasters had blown their bodies and souls into a plume of dust that filled the judgement hall, invading his sockets, his breath, his torn-open skull with the ash of their remains. He could feel the jagged fragments of their intent still trying to scour him like the bites of tiny insects swarming over his already crumbling body.

_ None of this depends on simple creations like you and me. _

It was all pointless, in the end. He was just a tool, like Chara always said he was. All his decisions only made things worse. It was better when he didn’t try to think for himself. Believing he understood the difference between right and wrong was a joke. His choices were just an illusion of the control he’d never had. It was easier, safer, to just follow someone else’s orders and take satisfaction in knowing he could do it well instead of worrying about what he was doing or why.

How could he have been so stupid?

“How is it, Cross? Did you enjoy spending time with your memories?”

For a moment, the voice is indistinguishable from the phantoms of his past until a firm grip on his chin forces his head up. Cross blinks dazedly, reeling from the sudden contrast of Nightmare’s dark sillohuette against the endless white. The inky texture of his body glistens with swirls of indigo and cyan, beautiful and vivid after so long spent in a colorless void. Cross almost keens from sheer relief, leaning desperately into Nightmare’s hold.

Nightmare’s mouth stretches wide into a smirk that’s almost obscene.

“You seem to be in a much more agreeable mood. Have you reconsidered your apology?”

He barely remembers why he’s here any more, but the words spark a faint memory of resentment. Cross shudders, trying vainly to hold onto his anger, to the rebellious spark that kept him from yielding to either Frisk or XGaster’s demands, but almost immediately the passion of those feelings are quenched beneath a tide of self-hatred and regret. He slumps, defeated. 

“Yes,” he breathes fervently. When Nightmare tries to draw his hand away, Cross chases it, leaning forward until he’s almost overbalancing, teeth pressing to Nightmare’s knuckles like a kiss of fealty. His voice is little more than a torn whisper scratching its way out of his abused throat. It’s a struggle to make himself audible. “I’m s-sorry. Won’t happen again.”

“You’re much more sincere now,” Nightmare purrs approvingly, generously letting his phalanges linger. The contact feels so fucking good after the unbearable isolation that Cross can’t even find the cold, slick texture of Nightmare’s hands off-putting. “I see having some time to think has been good for you.”

Cross makes a vaguely affirming noise. He doesn’t care; he’ll agree to anything so long as Nightmare doesn’t leave again. He contorts vigorously against his restraints only to let out a guttural whine of dismay when Nightmare finally retreats further than he can follow. The loss is like a dash of cold on his face. He sits back on his heels in wide-eyed anticipation, not knowing what to expect; more pain or finally a hint of mercy?

Nightmare crouches down to his level, forearms draped casually over his bent knees, tentacles coiling idly behind him. “So tell me now, Cross...who do you belong to?”

There’s only one right answer. Cross shoves down the faint spike of misplaced outrage. It’s too late for pride to matter. “You, Nightmare.”

“That’s right,” Nightmare agrees, and the approval soothes something primal in Cross’s soul. “And what happens when I let you out of here?”

“I…” Cross blinks, confused. There’d been a plan, but...it was Chara’s plan. Cross was meant to be collecting new fragments to rebuild their world, but even though he could still feel Chara’s determination he didn’t have full access to the hack with part of his soul under Nightmare’s seal, or perhaps he just didn’t understand how to use it properly on his own. Either way, he can’t collect the proper materials he needs, and even if he could it seems unimportant now. There’s only one thing that matters. “Whatever you want.”

A tentacle surges towards him. Cross braces, expecting to be hit, but instead it coils harmlessly and strokes the top of his skull. “You really do learn quickly. I knew I was right to choose you.”

The gentle petting continues long enough for the tension in Cross’s spine to unwind. He sinks into it, forgetting the burning ache in his limbs which have been bound immobile for far too long and the rough chafing on his wrists and ankles where the manacles have scraped his bones raw. He basks in Nightmare’s attention, letting every other thought slip away. He almost doesn’t notice when Nightmare’s other appendages circle around him, deftly unlocking the cuffs with a flare of magic. Cross can move again, but he doesn’t try to. Nightmare hasn’t asked him to.

“Cross.”

He doesn’t know when his sockets slipped shut, his mind drifting towards exhausted unconsciousness, but immediately they snap open again. His eyelights seek out Nightmare’s face, his posture tense and attentive.

Nightmare offers his hand, an unexpected courtesy. “It’s time to go.”

It’s not so much an impulse to obey as it is a compulsion. Cross takes Nightmare’s hand unthinkingly, but despite his willingness his body isn’t up to the task. The circulation of his magic has stagnated. Moving again after so much stillness is agony. He pushes through it, fighting the spots in his vision, and is surprised to fight Nightmare’s tentacles curling around him to assist. They support his shaking limbs, lifting him up so he can take a single, staggering step.

Right into Nightmare’s arms.

“That’s right,” Nightmare coos. The white void is fading from Cross’s vision, melting like a mirage, leaving behind the familiar brick and mortar walls of Nigthmare’s castle. The change is almost too much, overwhelming to Cross’s senses. He buries his face in Nightmare’s shoulder, clinging desperately. “Welcome to your new home.”

Cross shudders in relief and sinks bonelessly into Nightmare’s arms. He doesn’t need to rebuild his home, he realises distantly. He already has one. 


End file.
